thats pretty simple...make your starting hill, then your first jump. Get on starting hill and haul ass down it and hit the first jump. Adjust first jump accordingly. A few visits to other tracks will give ya good idea of what the dimensions would be.
Id love to build a track, but it would probably resemble the olympic track or the sweet track in Vegas, and never get sanctioned. None of this roller crap. Youd spend just as much time in the air as you would on the ground. (IMG:style_emoticons/default/smile.gif
Id give anything to ride some of the old 80s tracks. There was a discussion not too long ago about trying to build an 80s style track. Think it fizzled tho.